The "Big Four" accountancy firms

The "Big Four auditors" are the largest multinational accountancy firms.

• PricewaterhouseCoopers
• KPMG
• Deloitte Touche Tohmatsu
• Ernst & Young

These firms are associations of the partnerships in each country rather than having the classical structure of holding company and subsidiaries, but each has an international "umbrella" organization for coordination (technically known as a Swiss Verein).

Before the Enron and other accounting scandals in the United States, there were five large firms and were called the Big Five: Arthur Andersen, PricewaterhouseCoopers, KPMG, Deloitte Touche Tohmatsu and Ernst & Young.

On June 15, 2002, Arthur Andersen was convicted of obstruction of justice for shredding documents related to its audit of Enron. Nancy Temple (Andersen Legal Dept.) and David Duncan (Lead Partner for the Enron account) were cited as the responsible managers in this scandal as they had given the order to shred relevant documents. Since the U.S. Securities and Exchange Commission does not allow convicted felons to audit public companies, the firm agreed to surrender its licenses and its right to practice before the SEC on August 31, 2002. A plurality of Arthur Andersen joined KPMG in the US and Deloitte & Touche outside of the US. Historically, there had also been groupings referred to as the "Big Six" (Arthur Andersen, plus Coopers & Lybrand before its merger with Price Waterhouse) and the "Big Eight" (Ernst and Young prior to their merger were Ernst & Whinney and Arthur Young and Deloitte & Touche was formed by the merger of Deloitte, Haskins and Sells with the firm Touche Ross).

Enron turned out to be only the first of a series of accounting scandals that enveloped the accounting industry in 2002.

This is likely to have far-reaching consequences for the U.S. accounting industry. Application of International Accounting Standards originating in International Accounting Standards Board headquartered in London and bearing more resemblance to UK than current US practices is often advocated by those who note the relative stability of the UK accounting system (which reformed itself after scandals in the late 1980s and early 1990s). Accounting reform of a far more comprehensive sort is advocated by those who see issues with capitalism or economics, and seek ecological or social accountability.